Automatic telephone system



Aug. 9, 1932. F. GoHoRl-:L 1,870,448

AUTOMATIC TELEPHONE SYSTEM Original Filed Dec, 19, 1927 un l\ Iliff-dwf FE1-nani Cmhnrel Patented Aug. 9, 1932 1,370,448

Unirsesrarss PATENT orFicE FER/NAND GOHOREL, OF PARIS, FRANCE, ASSIGNOP., BY MESNE ASSIGNMENTS, TO AS- SOCIATED ELECTRIC LBORATORIES, INC., OF CHICAGO, ILLINIS, A CORPORATION OF DELAWARE AUTOMATIC TELEPHONE SYSTEM @riginal application tiled December 19, 1927, Serial No. 241,018. Patent No. 1,842,602, dated January 26, 1932. Divided and this application filed January 24, 1931. Serial No. 510,914.

The present invention relates in general tion are claimed in Patent No. 1,670,303, to automatic telephone systems but is conissued May 22, 1928, of which the instant cerned more particularly with such systems application is a division. Accordingly, only in which the toll or long distance connections such objects and features will be claimed in f, are established automatically. One of the the instant case which are not protected in v50 objects of my invention may be said to conthe parent application and in another divisist of the production of new and improved sional application Serial No. 241,018, filed toll repeater circuits whereby a subscriber December 19,1927. These features may be can operate automatic switches in a distant found in circuits and operations oi the ren, exchange to extend a connection to a desired peater and associated line switch, and con- 55 called line. sist chie-ily in novel provisions for reversing in such systems toll charges may be ascurrent over the calling` subscribers line sessed against the calling subscriber by by means of a polarized relay connected in operating his message register a numberoi a simplex circuitr to the toll line; in a prey: times to assess a line charge when the called selecting line switch whose 'control circuitis 50 party answers and thereafterreoperating the closed by a relay operated over a simplex register at stated intervals to assess an Circuit; and in the operation of a. two-stage elapsed time charge proportional to the relay controlling the line switch. length of the conversation. Accordingly, a Other objects of this invention will be apo 'further object of my invention lies in imparent. from the detailed description and 55 Y 'l respond with the number ot toll lines, a conand bankV contacts 7 5-77 The relay 64 is proved circuits 'for the control of the mes claims which follow. sage register to assess toll charges. rlhe accompanying drawing shows dia- Toll lines, to be eiliciently used, must grammatically at R 'a repeater, which can handle traffic in both directions. Therefore, be used for incoming and outgoing calls, toeach end ot' the toll lineV must be equipped gether with its arrangement for multiple me-r 70 with incoming switches. In the usual practering the duration of a call; it also shows tice, a selector is associated with the incomat C a preselecting secondary line switch. ing repeater to handle incoming calls, in This switch comprises a group of two relays which case the number oi selectors must cor- 63 and 64,- a rotary magnet 71, wipers 79.-74,

siderable saving in the number of selectors provided with a locking device, which prerequired can be effected by the use of a line vents all its contacts except the contact 68 switch associated with the incoming repeater from operating. Vlien the relay 63 is enerfor the above purpose. This line switch may gized, the locking device of the relay 64 is have access to a small number oi incoming` sereleased thus enabling all the contacts of the E0 lectors or may havev access to the regular local relay 64 to operate. selectors. For such use a preselecting line At the incoming end the toll line represwitch is preferable. Accordingly, a tursented by the conductors 7 8 and 79 terminates y ther object ot my invention may bey said to in a repeater similar to the repeater R, and n "m consist ot an improved preselecting rotary the description of its operation at the cxlin-e switch adapted to work in connection change where the line comes in is made with with the repeater hereinbetore set forth, to reference to the apparatus shown at R and C. complete incoming calls from a distant eX- An outline will now be given of the operchange. ation of the system. 45 Some ot' the above features of this inven- When theV calling subscriber has been con- 9U nected to a repeater such as the repeater R, which serves a toll line, he takes into use an incoming selecting device at the distant exchange over a repeater, such as R, and a secondary line switch such as C. In response to the operation of the calling subscribers number dial, the repeater R at the outgoing exchange transmits current iinpulses over both the line leads in parallel.

The repeater R at the incoming exchange transforms these impulses into other im-V pulses suitable for operating the selecting devices at the incoming exchange.

When the wanted subscriber answers, the current in the toll line is reversed and sets in operation the metering device. The operation of the calling subscribers meter is retarded suiliciently long to enable him to ascertain that he has obtained a connection with the wanted number. If the conversation exceeds a. predetermined length of time, the calling subscribers meter is operated a Second time, but a few seconds before this second operation is effected, the subscriber is warned by a special tone put on his line.

When the calling subscribers instrument has been connected over a selector to the repeater R, the relay 6 is energized in the circuit: battery, upper winding of the relay 6, back contact 18, bank contact 2 of the selector, the calling subscribers line and instrument (not shown), selector bank contact 4, back Contact 19, lower winding of relay 6 and ground.V Upon energizing, the relay 6 closes a circuit at the impulse cont-act 21. The relay 7 is energized in the circuit; ground, winding of relay 7, front contact 20, resistance 83 and battery; at the front contact of 25 it put-s ground on the test contact 3 of t-he selector bank, thus marking the line engaged and holding the selector in its operated position..Y

At the front contact 23, the relay 7 prepares the circuit of the relay 8; at the front Contact of 26, it prepares the circuit of the interrupter M1 over the electromagnet 17, and at the front of 24 it closes the circuit of relay 12 and ofthe left hand winding of relay 13. As the relay 13 is polarized, it is not operated in this circuit. Upon energizing, the relay 12 at the back contacts 39 and 41 disconnects the repeating -coil T from the secondary line switch, and at the front contacts it connects the coil to the calling line. At the contact 40 the ground on the lead in series with the relay 14 and the right hand winding of the rela-y 13 is disconnected and is replaced by the battery in series with the resistance 22 and the contact 21.,

This battery, being connected to the two conductors of the toll line, causes the energization of a relay corresponding to the relay 14 at the repeater at the distant exchange over the following circuit: battery, resistance 22, 'front contact 21, front contact of 40, right hand winding of the relay 13,V winding of the relay 14, the two windings of the repeater T in parallel, the two leads 78 and 79 of the toll line, the two windings of a repeater similar to the repeater coil T at the repeater in the incoming exchange such as R, the relay 14, the right hand winding of relay 13, the back Contact of 40, back contact 49 and earth.

At the repeater at the incoming exchange, the relay 14, on energizing, closes the front contact of 44, thus establishing the circuit of relay 15, and at the front contact of 43 it prepares a loop across the line of the secondary line switch C. The relay 15 is energized in the following circuit: ground, back contact of 24, winding of relay 15, front contact of 44, resistance 83 and battery. At the front Contact of 45 relay 15 puts ground on the test contact 3 in the selector bank over the back contacts 25 and 34, thus marking the line engaged at the selector in the incoming exchange; at the contact 48 it closes a circuit over one winding of the relay 16; at contact 46 it prepares the circuit of the relay 8; and finally, at contact 47 it completes the loop across the line of the secondary line switch in series with the left hand winding of .the relay 16. The direction of the current in the relay 16 is such that the relay does not operate its contacts.

The secondary preselecting line switch C, located at the incoming exchange, the operation of which will be hereafter explained, is always set on the line of an idle selector, and upon the energization of the relays 14 and 15, the circuit of the relays 63 and 64 is closed over: battery, contact 70, windings of the relays 64 and 63, backcontact of 66, lead 61, back contact of 41, front contacts of 43 and 47, winding (left hand) of the relay 16, back contact of 27, lead 62, back contact of G9 and ground.

Upon energizing, the relay 63 operates a locking device, thus enabling relay 64 to actuateall its contacts; at the back Contact of 65 it disconnects ground from the circuit of the magnet 71, and at the 'front contact of 65 it establishes a locking circuit in series with the relay 64. The relay 64, on energizing, connects the line to the selecting device at 66 and 69, and opens the circuit of the rotary magnet at 67. f

When the line is connected to the selecting device (not shown), its calling relay is energized in series with the line loop and closes the circuit of the releasing relay, which puts ground on the test lead and test contact 75. By means of the wiper 72, this ground is connected to the end of the winding of relay 64, and the relay 63, being short circuited, releases, while the relay 64 remains energized.

The toll line has now been connected across the repeater R over the selecting device in the incoming exchange.

At the outgoing exchange, the relay 14 of the repeater is also energized in the circuit above described, but this has no effect because the circuit of relay 15 is open at the back contact of 24.

lVhen the subscriber operates his number dial for the remaining gures of the wanted subscribers number, each interruption of the line by the number dial causes the relay 6 to open the contact 21 and at back contact 20 it closes the circuit of relay 8. The latter, on energizing, opens the circuit of the left hand winding of the repeater T and suppresses. the etfect ot the condenser 80 on the relay 6 during the impulses.

The short circuiting of the relay 7 having rendered it slow acting, it remains operated during the impulses and the relay 8, after having been energized, likewise does not release until after the train of impulses.

At the incoming exchange, the relay 14 releases each time its circuit is opened at the contact 21 oit' the relay 6 in the repeater at the outgoing exchange, and at its contact 43 it repeats these interruptions in the line ot' the selecting device for the purpose of positioning the wipers of the latter onto the line of the wanted subscriber. At the back contact of 44, the circuit of the relay 8 is closed and the relay on energizing prepares at the front contact of 27 a new circuit for the impulses, Which does not pass over the winding of the relay 16. The short circuiting of the relays 15 and 8 having rendered them slow acting, they remain in their operated position during the train of impulses, and then the relay 3, on releasing, connects the repeater to the line of the selecting device and closes the loop over the winding of the relay 16.

Vhen the wanted subscriber responds to the call, the current is reversed in the line oi'l the selecting device and hence in the left hand winding of the relay 16, and this reversal energizes the relay 16. Thereupon the relay 16 opens the circuit of the relay 8 at contact 50; it short circuits the contact 43 of the relay 14 at contact 51, and at the contact 49 it replaces the ground connection by the special battery B2 in series with the resistance 57. The voltage of this special battery B2 is greater than the central battery of the exchange, hence the direction of the current in the toll line is reversed.

This battery reversal on the toll line causes the relay 13 to be energized at the repeater in the outgoing exchange. The relay 13, on energizing, at 42 closes the circuit of the relays 5 and 10. On energizing, the relay 5 reverses the battery on the line of the calling subscriber. Thus supervision is obtained. The relay 10, on energizing, closes the circuit at 33 for maintaining its upper winding energized; at contact 34 it connects the test lead to the contacts ot the metering relay 9; at contact 32 it prepares a locking circuit for its lower winding; at 31 it opens the release circuit for the magnet 17; and at 35 it closes the circuit of this magnet over the interruptor M1, which operates slowly.

It will be assumed that the wanted subscriber belongsto an exchange for which a three minute conversation costs three times as much as a loc-al call. In that case the blank contacts of the apparatus, which has 25 contacts, are connected in multiple as shown in the iigure, and the interrupter M1 closes its contact every 7.2 seconds. As the metering relay 9 is connected to the fourth, sixth and eighth bank contact, the first operation of the subscribers meter is delayed for about 20 seconds, thus giving the calling subscriber time to release the connection before metering it for any reason he linds ie is not connected to the wanted party.

When `the wiper 54 reaches the fourth bank contact, the relay 9 is energized in the following circuit; ground, wiper 54, fourth bank contact, lead 58, back contact of 37, winding of the relay 9 and battery. @n energizing, the relay 9 at its contact 30 replaces the ground on the test lead by the special battery B3, for operating the calling subscribers meter, and at contact 29 it closes the circuit for the lower winding` of the relay 10.

At the moment this latter circuit is without effect, as the relay 10 is energized by its upper winding. l/Vhen the wiper 54 passes onto the fifth bank contact, the relay 9 releases, which causes the meter of the calling subscriber to fall back likewise after having registered one unit. At the sixth and eighth back contact the meter is again oper ated, so that when the wiper 54 reaches the ninth bank contact, the calling subscribers meter will have registered three units.

By the action of the magnet 17, the wiper 54 continues its rotation and, on reaching its last bank contact, it closes the circuit of the relay 11 over; ground, wiper 54, 25th bank contact, lead 56, lower winding of the relay 11 and battery.

On energizing, the relay 11 at its contact 38 puts a tone on the calling subscribei"s line to notify him that his meter is going to be again operated.

It the calling subscriber replaces his rcceiver before the wiper 54 for the second time and at contact 31 it closes the circuit for automatically operating the magnet 17.

If the wiper 54 is out of its normal position, the contact 53 is closed and the circuit 5 of the magnet 17 is closed from battery, the

winding of the magnet 17, the contact 52, the contact 53, the upper winding of the relay 11, the back contacts of 31, 23, 20 and to ground.V The magnet 17, operating intermittently, advances the wiper 54 to its normal position, in which the contact 53 isy opened and the wiper comes to rest.

The relay 11 is energized in series with the magnet 17 and puts ground on the test lead of the repeater over the contacts 36, 25 and 34, thus preventing the repeater from being taken into use before the wiper 54 reaches its normal position.

The relay 12, on releasing, connects the toll line to the secondary line switch, and at contact 40 it again puts ground on the lead 60 in series with the relay 14. At the incoming exchange the relay 14 releases when the relay 6 at the outgoing exchange has released, whereupon the relay 15 likewise releases; the loop across the line of the selecting device is opened and this is released. At the same time the ground is removed from the test lead and the relay 64 of the secondary line switch releases. At the repeater, the relay 16y releases when the circuit of its left hand winding is opened at 43, and when it has fallen back, ground is again put on the lead in .series with the relay 14.

If the calling subscriber hangs up his receiver while metering is taking place, the release of the switches at the incoming eX- change takes place in the manner above described, but at the outgoing exchange relay 1() remains locked until the metering has been completed. Thereby its lower winding is connected to the fifth and seventh bank contacts over the front contact of 32, and from the fifth to the eighth contact the circuit of its lower winding is closed either at contact 29 or by the wiper 54.

When the calling subscriber has hung up his receiver the relays 5, 6, 7, 12, and 13 fall back as in the case described above, but the preceding selecting devices are not released, because ground or special battery B3 is connected to the test lead at the contacts 30 and 34. Vhen the relay 7 falls back, the circuit of the rotary magnet 17 is connected to the 5 interrupter M2 at the back contact of 26.

This interrupter operates quicker' than the interrupter M1. Accordingly, the magnet 17 operates at such rate that theV wiper 54 moves too fast for the meter to operate when '0 the wiper passes over the metering contacts.

The circuit of the lower winding of relay 10 is opened when the bank Contact 9 is reached,

and upon falling back, the relay causes the wiper 54 to stop, as described in the preced- 5 ing case, in its normal position.

Y' If 'the calling subscriber should hang Vup his receiver before metering has commenced, the magnet 17, in operating automatically, returns the wiper 54 yto its normal position, and the relay 11, on energizing in series with the magnet, opens at 37 the circuit of the metering relay 9 in order to prevent its operation when the wiper 54 passes over the metering contacts.

The function of the secondary switch C is to connect the toll line, to which it belongs, with the line of an idle selecting device; hence when the line, on which the wipers 72, 73 and 74 are standing, is taken into use, ground is placed on the test lead and test contact, such as the contact 75, and the test wiper 72 connects this ground to the winding of the relay 64. On energizing, the relay 64 only operates the contact 68 owing to the lockingdevice, and the circuit of the magnet 71 is closed as follows: earth, back contact of 65, back contact of 67, front contact of 68, winding of the magnet 71 and battery. The magnet 71, on energizing, opens at the circuit of relay 64, which on releasing ope-ns at 68 the circuit of the magnet. Y The inagnet, on returning to normal advances its wipers onto the contacts of the nextline. This rotary `movement continues until the wipers find a free line. If during this movement the switch is taken into use by a toll line, the relay 63 is not energized because it is short circuited by ground on the test wiper; hence the relay cannot be energized unless the wipers are standing on an idle line.

, If the wipers are standing on an idle line when the switch is taken into use by a toll line, the relays 63 and 64 are energized in series by the loop over the two leads of the line 61 and 62, and in that case the relay 64, being unlocked by the relay 63, yoperates all its contacts, and the switch operates in the manner already described.

Vhat is claimed is:

1. In an automatic telephone system, a non-numerical switch, trunk lines accessible thereto terminating .in contacts, means for making certain of said trunks busy, wipers for said switch normally standing on the contacts of one of said trunk lines, a relay in said switch operable in two stages, a motor magnet for said switch, said relay operated in one stage whenever the trunk line upon whose contacts the wipers are standing becomes busy, means controlled by the operation of the relay in said one stage for causing the operation of the motor magnet to move the wipers into engagement with the contacts of another trunk line, and means for operating said relay in its second stage to extend a connection to an idle trunk line.

2. In an automatic telephone system, a non-numerical switch, trunk lines accessible thereto terminating in contacts, means for making certain of said trunks busy, line and test wipers for said switch normally standing on the contacts ci one of said trunk lines, a relay in said switch operable in two stag-es, a motor magnetl for said switch, a circuit for said relay including said test wiper and the associated trunk contact, said relay operating to its first stage over said circuit when the trunk line becomes busy to operate said motor magnet to move the wipers into engagei'nent with the contacts of another trunk line, and means for operating said relay in its second stage to extend a connection to an idle trunk line.

3. In combination with a group of lines, a line hunting switch; means for making any line busy, means in said switch operative, consequent to a lin-e with which the switch is associated becoming busy, to automatically cause said switch to become associated with another of said lines; a second means, operative, in conjunction with said rst means consequent to the seizure of said switch, to extend a connection over any idle line with which it may be connected, and means for preventing said second means from operating while the switch is associated with a busy one of said lines.

4l. In an automatic telephone system, a non-numerical switch, trunk lines accessible thereto terminating in contacts, means tor making certain ot said trunks busy, wipers for said switch normally standing on the contacts of one of said trunk lines, a relay J in said switch, a motor magnet for said switch, means for operating said relay whenever the trunk line upon whose contacts the wipers are standing becomes busy, means controlled by the operation of the relay for then causing the operation of the motor n' magnet to move the wipers into engagement with the contacts of another trunk line, and means for also operating said relay consequent to the seizure of said switch to extend a connection to an idle trunk line.

5. In an automatic telephone system, a non-numerical switch, trunk lines accessible thereto terminating in contacts, means for making certain of said trunks busy, line and test wipers for said switch normally standing on the contacts of one ot said trunk lines, a relay in said switch, a motor magnet for said switch, a circuit Jfor said relay including said test wiper and the associated trunk contact, said relay operating over said circuit when the trunk line becomes busy to operate said motor magnet to move the wipers into engagement with the contacts of another trunk line, and means for operating said relay in a different manner to extend a connection to an idle trunk line.

6. In an automatic telephone system, a trunk hunting switch, means for seizing said switch to extend a connection in the direction of a called line, a line relay for said switch having an operating circuit including a wiper of said switch, a stepping circuit for said switch under cont-rol of said line relay for normally maintaining said switch associated with an idle trunk, a second circuit for said rela-y including a wiper cut-through relay, and means under control of the wiper cut-through relay for preventing the line relay trom closing said stepping circuit when the switch is seized.

In witness whereof, I hereunto subscribe my name this 30th day of December, A. D.

FERNAND GOHOREL. 

